1. Field of the Invention
The present invention is related to jumper or booster cables, and in particular to jumper cables having protective circuitry to prevent reverse connection or short circuiting of the cable connectors.
2. Description of the Prior Art
There are many situations in which a vehicle's regular battery can become run down or otherwise defective to the point of not being able to furnish sufficient direct current (DC) power to start or maintain operation of the vehicle's engine. One common method of starting a "disabled vehicle" with a dead or defective battery is by use of "jumper cables". In this method, a vehicle (the "rescue vehicle") which is running is used to provide electrical power to the "disabled vehicle". The jumper cables are a pair of electrical conductors having clamp-type connectors at their ends which are used to clamp onto electrical terminals of the rescue vehicle and the disabled vehicle.
Typical jumper cables are color coded, with one cable being black and the other cable being red. The red cable is for connection between the positive terminals of the rescue vehicle and the disabled vehicle, and the black cable is for connection between the negative or ground terminals of the rescue vehicle and the disabled vehicle.
Despite the color coding of the jumper cables, reverse polarity connections are possible. This is particularly the case when persons who are generally unfamiliar with the electrical system of the vehicle or unfamiliar with the use of jumper cables attempt to connect and use the jumper cables. The reverse polarity connection of the cables, or the shorting of the connectors of the cable, can result in arcing, thereby creating a risk of igniting acid fumes around the battery and producing an explosion. In the event that a reverse polarity connection is made, not only the battery of the disabled vehicle can be damaged, but also electrical components of the electrical system, such as the alternator diodes, can be damaged.